The length of a Pomodoro, 25 minutes, seems short enough to make it possible to resist being
distracted by various kinds of interruptions.

This seems to suggest that 25 minutes is just a random duration taken by the author which happens to work for him and which many people now seem to use. Are there any scientific studies that indicate that 25 minutes is the optimal time (for most people and most tasks) for a pomodoro?

25mins duration is not the best in Scientific dimention. But you should not forget that things that block you to complete your tasks are interruptions. 25mins is not too long for any interruptions to wait. It increase your capability to manage your interruptions.
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Amp TanawatDec 23 '12 at 16:39

It says in the book that they've experimented with it and found it as the ideal duration. Exact quote from the book:

Note In various work groups which experimented with the Pomodoro Technique in mentoring
activities, each team was allowed to choose the length of their own Pomodoro on the condition
that this choice had to be based on observations regarding effectiveness. Generally, the teams
started off with hour-long Pomodoros (25 minutes seemed too short at first), then moved to 2
hours, then down to 45 minutes, then 10, till they finally settled on 30 minutes.

Since they've been using the Pomodoro technique for a few years, I assume that it's the tried and true ideal length.

I think you have to factor into this how many Pomodoro's you're going to want to do in a day plus when and how long your breaks (shorter ones and longer ones) are going to be - and quite possibly how much of a procrastinator you are.

If my Pomodoros were always one hour long, I'd probably delay starting them as long as I could as the prospect of one hour of concentrated work on a boring / repetitive tasks seems daunting. However, if it's only 25 minutes, you can look forward to the 5 minute break you are soon going to enjoy...

So if I had a window of two hours I could work in and went with two 1-hour Pomodoros, procrastination might result in me getting less work done compared with 25-minute Ps with more break time in between.

I think it would depend on the activity being performed. If it is something that you already have neuropathways burned in for then you can go a lot longer without a break. If you are learning it for the first time or reinforcing weak neuropathways then I'd say you'd want a shorter Pomodoro time. When learning, you need to both focus and defocus. This is based off of my own experience doing Pomodoros both working and learning new things such as programming, guitar, and languages.

The question is about scientific studies, not about "I think".
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Jan DoggenApr 21 at 0:30

For what its worth, I'm very scientific in evaluating what affects my productivity. Just because I haven't submitted a peer reviewed paper does not mean my suggestion is unscientific or invalid.
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PhoenixFFApr 22 at 2:41